Security or identification markers are provided to enable validation of an item. The need for security or identification markers for valuable items is well-known. Banknotes typically include advanced security features, such as watermarks, fluorescent inks and holograms. However, with advances in copying technology it is becoming harder to install security features that are difficult to counterfeit, quick and easy to detect in situ, and cheap enough to mass produce.
Chemical and biochemical labels or tags are added to items as markers that can be detected to validate these items. However, validation typically involves removal of the marker from the item before analysis can be carried out. This is both time-consuming and expensive, rendering such markers inappropriate for on-line, high-speed examination.
Optical-based techniques have been used for the encoding of a range of products. One widely-employed optical labeling strategy uses fluorescent labels, the material of which emits light when excited by radiation of a particular wavelength. An example of a particular type of fluorescent material is described in EP 1 491 350 to NCR International, Inc.
Another frequently used marker is a security hologram. Holograms are records of an interference pattern formed by light at a recording location. Holograms can be applied to an item to prevent or reduce the counterfeiting of the item and may be used to authenticate an item because the three-dimensional image which they provide is difficult to reproduce. Examples of holograms are described in WO 97/40464 to Advanced Deposition Technologies, Inc.
All of the markers described above are expensive and complicated to produce if they are designed as unique pieces. However, if they are mass produced cheaply, they are no longer unique pieces. Therefore, there is a need for unique security and authenticating markers that are inexpensive to produce yet difficult to copy.
It is an object of the invention to provide more cost-effective, unique labels for security or identification systems.
It is a further object of the invention to provide a method and systems for authenticating an item containing a security or authentication label.